The Mode Hop Fix circuit corrects for the exposure errors that occur due to laser mode hops. Mode hopping is a characteristic of semiconductor lasers where the output emission wavelength can jump suddenly as the operating condition of the laser changes. Mode hops can be caused by changes in the laser's temperature and optical feedback. Mode hops cause exposure changes in two ways. First, the emission efficiency of the laser generally changes when the mode hops resulting in an obvious change in exposure. Second, the emission wavelength changes when a mode hop occurs. If the media's response curve isn't sufficiently flat it is possible that noticeable exposure changes will occur.